% conclusion
In this short paper, we have motivated the use of \st{s} for the task of document retrival. We have
shown how this task can be approached by implementing the \doclists{} framework. Using this
framework, we built a \st{} for a small set of test corpora and showed that it is possible to search
the resulting tree for relevant documents with respect to a query.

One problem we had to face when deciding on JAVA as the language of choice is its limited ability to
deal with disk I/O processes, especially the way JAVA handles the serialization of arbitrary objects.
\\
The JAVA standard library provides for serialization via an interface that stores and loads complete
objects only, including all sub-objects it may be comprised of. For our purposes, this is clearly a
disadvantage, as \st{s} can grow into very large objects depending on the number of documents stored
in them, and the length thereof.
\\
To deal with this limitation, we are currently in the progress of implementing our own interfaces
for disc-based input-output-operations, with which we will be able to use a b+Tree representation
for \st{s}. This will enable us to break down trees into chunks of bytes that can be written to and
read from disk as they are needed, i.e., we only have to load chunks of the tree into memory that
are actually needed at access time.

Further improvements we aim for in future iterations of the software are the implementation of
complex search queries in the style of regular expressions, using operators such as "AND"/"OR", as
well as experimenting with alternative search- and weighing-algorithms for the retrieval task.

The \doclists{} framework is made available under the terms of the GPL v2\footnote{http://www.gnu.org/licenses/old-licenses/gpl-2.0.html}
and can be retrieved via its google code page\footnote{http://code.google.com/p/doclists/}.
